Does multi-specific synchronous spawning cause hybridization and speciation in Acropora?

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K07545
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Biodiversity/Systematics
• Research Institution: Okinawa National College of Technology
• Principal Investigator: Isomura Naoko 沖縄工業高等専門学校, 生物資源工学科, 准教授 (90376989)
• Co-Investigator(Kenkyū-buntansha): 深見 裕伸 宮崎大学, 農学部, 教授 (50402756) ; 守田 昌哉 琉球大学, 熱帯生物圏研究センター, 准教授 (80535302)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 雑種種分化 / ミドリイシ / 遺伝子浸透 / 多種同調産卵

Outline of Final Research Achievements

Our study aims are to elucidate the effect of frequency about multi-specific synchronous spawning in Acropora on introgression and hybridization-speciation. We set two study sites, one was Akajima Island where multi-specific synchronous spawning was found every year, another was Sesoko Island where multi-specific synchronous spawning did not always occur. From field survey and genetic analyses about Acropora populations in the two sites, we found results as follows: 1) In Sesoko Island, multi-specific synchronous spawning was found irregularly, 2) In Akajima Island, remarkable introgression was confirmed between Acropora florida and A. gemmifera they have almost same spawning time.
Now we continue to perform genetic analyses about Acropora population in Sesoko Island, by the results of the population in Akajima Island, we concluded that multi-specific synchronous spawning may affect introgression among Acropora.

Free Research Field

繁殖生態学

Academic Significance and Societal Importance of the Research Achievements

ミドリイシ属は、多種多様な形態を示す約150種から構成される有藻性イシサンゴ類の中で最大のグループである。この多様性がどのように生じてきたかは長い間謎であり、雑種種分化によると考えられてきた。今回の課題を含めた代表者らの研究から、そもそも物理的に雑種体を生じるために必要な多種同調産卵は限られた地域でのみみられること、さらに多種同調産卵がみられる地域のミドリイシでは遺伝子浸透は生じているものの、雑種体が種として確立・継続していくにはいくつもの条件をクリアする必要があることがわかった。以上からミドリイシの多様化には、物理的に種間交配できる多種同調産卵が重要な役割を担っていると考えられた。